Re: Re: AX84 Variable Bias

[beelzebum]

The mid, bass, and treble caps should all be blocking about 130v. if you are reading 130v across them, then they are blocking the dc from pin 3 of your cathode follower. This is what you would want to see. If you read 0v across any of those then that is a problem. That would mean that it was shorted. Take a voltage reading from your caps on the tone stack side to ground to see if there is any voltage leaking into your tone stack. also if you are reading 30v at you grid and only 28v at your cathode, then your bias voltage is positive 2v and you are melting your tube. If your cap is leaking voltage into your tone stack then it would also be dumping a positive voltage onto your grid. check your caps you should read a voltage across them, that means they are blocking your dc.